The human heart relies on a series of one-way valves to help control the flow of blood through the chambers of the heart. For example, referring to FIG. 1, deoxygenated blood returns to the heart 20, via the superior vena cava 22 and the inferior vena cava 24, entering the right atrium 26. The heart muscle tissue contracts in a rhythmic, coordinated heartbeat, first with an atrial contraction which aids blood in the right atrium 26 to pass through the tricuspid valve 28 and into the right ventricle 30. Following atrial contraction, ventricular contraction occurs and the tricuspid valve 28 closes. Ventricular contraction is stronger than atrial contraction, assisting blood flow through the pulmonic valve 32, out of the heart 20 via the pulmonary artery 34, and to the lungs (not shown) for oxygenation. Following the ventricular contraction, the pulmonic valve 32 closes, preventing the backwards flow of blood from the pulmonary artery 34 into the heart 20.
Oxygenated blood returns to the heart 20, via the pulmonary veins 36, entering the left atrium 38. Left atrial contraction assists blood in the left atrium 38 to pass through the mitral valve 40 and into the left ventricle 42. Following the atrial contraction, ensuing ventricular contraction causes mitral valve 40 closure, and pushes oxygenated blood from the left ventricle 42 through the aortic valve 44 and into the aorta 46 where it then circulates throughout the body. Under nominal conditions, prolapse of mitral valve 40 is prevented during ventricular contraction by chordae 40A attached between the mitral valve 40 leaflets and papillary muscles 40B. Following left ventricular contraction, the aortic valve 44 closes, preventing the backwards flow of blood from the aorta 46 into the heart 20.
Unfortunately, one or more of a person's heart valves 28, 32, 40, and 44 can have or develop problems which adversely affect their function and, consequently, negatively impact the person's health. Generally, problems with heart valves can be organized into two categories: regurgitation and/or stenosis. Regurgitation occurs if a heart valve does not seal tightly, thereby allowing blood to flow back into a chamber rather than advancing through and out of the heart. This can cause the heart to work harder to remain an effective pump. Regurgitation is frequently observed when the mitral valve 40 fails to properly close during a ventricular contraction. Mitral regurgitation can be caused by chordae 40A stretching, tearing, or rupturing, along with other structural changes within the heart.
Neochordal replacement for stretched or torn chordae is one option to reduce regurgitation. In such a procedure, chords to be replaced are identified and dissected as required. A papillary suture is placed in a papillary muscle corresponding to the dissected chord. The papillary suture may optionally be pledgeted on one or both sides of the papillary muscle. A leaflet suture is also placed in the corresponding mitral valve leaflet. The papillary suture and the leaflet suture may then be tied or otherwise fastened together to create a replacement chord to help support the mitral valve leaflet and prevent regurgitation.
Regurgitation with the mitral valve or the aortic valve may also occur when the valve's leaflets are unable to coapt properly. In such a situation, if the leaflets are still viable, surgeons may determine that the improper coaption is caused by changes in the surrounding annulus tissue whereby the annulus has become distorted due to disease or patient genetics/aging. One possible treatment in such situations is a valve annuloplasty, whereby a device (typically a ring) is sutured around the heart valve to help pull the valve leaflets together.
In cases of stenosis, when a heart valve does not fully patent due to stiff or fused leaflets, blood flow tract narrowing, or obstructive material buildup (e.g., calcium), installation of a replacement heart valve may be more appropriate. In these situations, the diseased heart valve may be removed and then a replacement valve may be sutured into the surrounding tissue.
Unfortunately, while many of the above techniques are proven methods of heart valve repair, technical challenges impede their widespread utilization, especially in minimally invasive cardiac surgery. In particular, it is difficult and time consuming to manipulate a suture needle with forceps through a minimally invasive opening to place the sutures for neochordal replacement, valve annuloplasty, or valve replacement. An innovative system that remotely delivers and reliably secures suture for a variety of surgical situations would dramatically improve the accessibility and clinical outcomes following cardiac and other types of surgery.
Therefore, there is a need for an efficient and precise minimally invasive surgical suturing device that enables surgeons to utilize a minimal invasive entry point for cardiac and other procedures without sacrificing suturing effectiveness.